In recent years, containers having the thinnest possible walls are provided in order to reduce the amount of plastic that needs to be disposed. For example, a plastic container formed using a thin plastic laminate film is disclosed in Patent Document 1. This plastic container has a cylindrical shape with the bottom, and includes a trunk portion formed in a cylindrical shape using a plastic laminate film and molded portions coupled with one end and the other end of the trunk portion by insertion injection molding means.
Patent Document 1 discloses that a cylindrical element made of a plastic laminate film is attached to a mandrel used as a mold core in a manner covering the mandrel. In the technique described in Patent Document 1, the cylindrical element is attached to the mandrel in a manner covering the mandrel, and the mandrel is mounted on a molding tool. Thereafter, a melted plastic resin material is injected into a mold cavity within the molding tool by the insertion injection molding means, to form the molded portions connected to the one end and the other end of the cylindrical element, thereby molding the above plastic container.